Module mcp_server 

MCP server support for providing MCP tools over ACP Runtime-agnostic MCP server support for providing MCP tools over ACP.

This module provides the infrastructure for attaching MCP servers to ACP connections without tying the core SDK to a particular MCP implementation or async runtime.

Building MCP servers with tools

The agent-client-protocol-rmcp crate provides the builder APIs for MCP tools backed by the rmcp crate.

Custom MCP Server Implementations

You can implement McpServerConnect to create custom MCP servers:

use agent_client_protocol::mcp_server::{McpConnectionTo, McpServer, McpServerConnect};
use agent_client_protocol::{DynConnectTo, NullRun, Role, role};

struct MyCustomServer;

impl<R: Role> McpServerConnect<R> for MyCustomServer {
    fn name(&self) -> String {
        "my-custom-server".to_string()
    }

    fn connect(&self, cx: McpConnectionTo<R>) -> DynConnectTo<role::mcp::Client> {
        // Return a component that serves MCP requests
        DynConnectTo::new(my_mcp_component(cx))
    }
}

let server = McpServer::new(MyCustomServer, NullRun);

Structs

McpConnectionTo

Context about the ACP and MCP connection available to an MCP server.

McpServer

An MCP server that can be attached to ACP connections.

McpToolMetadata

Runtime-neutral metadata for an MCP tool.

McpToolRegistry

Runtime-neutral registry for MCP tools.

RegisteredMcpTool

A registered MCP tool that can be dispatched with erased JSON values.

Enums

EnabledTools

Tracks which tools are enabled.

Traits

McpServerConnect

Trait for types that can create MCP server connections.

McpTool

Trait for defining MCP tools.

Functions

tool_fn

Create a stateless function-backed MCP tool and its concurrent responder.

tool_fn_mut

Create a “single-threaded” function-backed MCP tool and its responder.

Type Aliases

McpToolSchema

JSON Schema object used to describe MCP tool inputs and outputs.